The present invention is directed to a method for the manufacture of a fiber with a tapered end having a refractive lens. In particular, a method wherein a fiber is heated while subjected to tensile forces to create a constriction therein, severed at the constriction to form two fibers having tapered ends and then melting the severed fiber to form the refractive lenses.
Transition modules, which have the highest possible incoupling efficiency of a semiconductor laser light into a monomode fiber and at the same time reflect little light back into the laser, are required in optical communication technology with monomode glass fibers. These demands are excellenty met by means of a coupling optics, which consist of a fiber with a tapered end having a refractive lens at the tapered end of the tapered fiber. The refractive lens can be produced by means of melting, for example, melting around the tapered end of a fiber taper as disclosed in an article by H. Kuwahara, S. Sasaki, and N. Tokoyo, "Efficient Coupling from Semiconductor Lasers into Single-Mode Fibers with Tapered Hemispherical Ends", Applied Optics, Vol. 19, No. 15, Aug. 1, 1980, pp. 2578-2583.
In order to manufacture such a fiber taper with refractive lens, one can proceed such that a stretched fiber is locally or topically heated up to the softening point of the glass so that a permanent constriction of the fiber will occur. Then the tension is removed before the fiber tears at the constriction. The constricted fiber is cut at a specific point of the constriction by means of a cutting tool. Then the refractive lens is melted or joined to the tapered end of at least one of the two fiber tapers such as by being melted thereon in a further work step.